A tapered roller bearing may include a retainer, a cage usually made from a steel plate. The retainer integrates an inner ring and rolling elements with each other. In an ultra-large tapered roller bearing which is often used as a main bearing in the field of wind power-generation, it is difficult to make a single-piece retainer from a steel plate.
As an alternative, therefore, there is proposed a welded retainer which includes support rods inserted through hollow rollers, and two side plates welded to the support rods. Another alternative is a segmented (divided) retainer which requires special fabrication method using dedicated jigs.
The first alternative has a problem of welding cost while the second alternative has a problem of handling difficulty. The second alternative, which was found to have some cost advantage, was improved further. As found in Patent Literature 1 and Patent Literature 2, in retainers used in large tapered roller bearings, an immobilizing member is arranged with a segmented retainer or a separated retainer on a circumference to prevent separation during assembly, for improved handling and assemblability. Also, Patent Literature 3 discloses an arrangement that a segmented retainer is immobilized by a ring member in order to prevent the segmented retainer from breaking apart during assembly.